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A study of void effects on the interlaminar shear strength of unidirectional graphite fiber reinforced compositesA study was conducted to evaluate the effect of voids on the interlaminar shear strength (ILSS) of a polyimide matrix composite system. The graphite/PRM-15 composite was chosen for study because of the extensive amount of experience that has been amassed in the processing of this material. Composite densities and fiber contents of more than thirty different laminates were measured along with ILSS. Void contents were calculated and the void geometry and distribution were noted using microscopic techniques such as those used in metallography. It was found that there was a good empirical correlation between ILSS and composite density. The most acceptable relationship between the ILSS and density was found to be a power equation which closely resembles theoretically derived expressions. An increase in scatter in the strength data was observed as the void content increased. In laminates with low void content, the void appears to be more segregated in one area of the laminate. It was found that void free composites could be processed in matched metal die molds at pressures greater than 1.4 and less than 6.9 MPa.
Document ID
19910002721
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Bowles, Kenneth J.
(NASA Lewis Research Center Cleveland, OH, United States)
Frimpong, Stephen
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1990
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NASA-TM-103267
NAS 1.15:103267
E-5704
Report Number: NASA-TM-103267
Report Number: NAS 1.15:103267
Report Number: E-5704
Accession Number
91N12034
Funding Number(s)
PROJECT: RTOP 510-01-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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